In New Zealand, black beetle (Heteronychus arator) most commonly feeds on pasture grasses and is also noted as a pest in many crops, including maize, sweet corn, potatoes, kumara, strawberries, cucurbits and brassicas. A succession of abnormally warm and dry summers can lead to an explosion in black beetle numbers and associated damage.
Key points
- Black beetle adults are a sporadic pest of seedling maize. Low numbers can cause economic losses.
- Climate limits the distribution of black beetle to the north of the North Island, coastal Taranaki and Hawke’s Bay.
- A succession of abnormally warm and dry summers can lead to an explosion in black beetle numbers and associated damage.
- Damage is characterised by a rough, rasped pattern on the bottom 3 cm of the plant stem.
- Black beetle damage can be reduced by delaying planting until mid-November, or the use of an insecticide seed treatment.
Click here to read Maize Update No. 81.